[Bug 53508] Performance XSSFCell.setCellValue(String) is very slow

[bu...@apache.org]

https://issues.apache.org/bugzilla/show_bug.cgi?id=53508

--- Comment #3 from velten@econda.de ---
I think we have found the real bug.

With JDK 7 there was implemented a new init method of HashMap and some other
Maps.

This new Init Method used the standard Random-Generator to calculate the
hashcode.

But this Random-Generator is synchronized. Causing problems in multithreaded
environment. There is no performance bug, when there is only one Thread. But in
multithreaded environment there can be a huge loss in performance.

This JDK-Bug is fixed with version 1.7.0_40.

After update to this version all seem to be fine now.

Please look at:

http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8006593

http://stackoverflow.com/questions/14010906/given-that-hashmaps-in-jdk1-6-and-above-cause-problems-with-multi-threading-how

https://blogs.oracle.com/henrik/entry/migrating_from_java_se_6

http://java-performance.info/changes-to-string-java-1-7-0_06/

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